POSSIBLE CAUSES OF COUNTERCLOCKWISE LOOP OF TROPICAL CYCLONES

The counterclockwise loop of a moving tropical cyclone in the model atmosphere is clearly shown in the numerical experiment by six sets of time integrations over periods longer than seven days in terms of a barotropical quasi-geostrophic model containing terms of environmental heating and dissipation. Numerical investigation is performed of the dependence of the abnormal path stability upon the computational domain size and the disturbance of the heat source, initial value and iterative precision, indicating that this type of path is a stabler form of motion for the cyclone in the model atmosphere. And the possible causes are presented.